Large vehicles such as coach buses, tractor trailers, commercial trucks are typically equipped with a compressed air brake system in which the brakes of the vehicle are actuated by compressed air. An air compressor is operated by the vehicle engine and storage reservoirs maintain a quantity of pressurized air for the brakes and other compressed air uses. Moisture, condensed water and oil are problems associated with compressed air systems and are particular problems that can adversely affect brake system operation. Therefore, an air dryer and an oil filter are usually incorporated in the compressed air system. The air dryer is effective at removing moisture, condensed water and oil vapor.
Traditionally, an air dryer has an air dryer valve body, a dryer cylinder, an air pressure governor, a backflow valve. One important function of the air dryer is to connect the air pressure governor and an air outlet through a long and narrow air passage 19′ as shown in FIG. 3 of a related art. This long and narrow air passage 19′ is very difficult to produce. Often time, the tool used to make such a long and narrow air passage breaks easily. It is for the drill to miss the target during the manufacturing process and causing compressed air leak. Manufacturing cost is driven higher due to the difficulties and higher rejection rate.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.